1. Field of the Invention
The present invention relates to an LED module for a flat panel display unit and, more particularly, to a plug-in type LED module wherein a number of LEDs are arranged in a matrix form.
2. Description of the Prior Art
A flat panel display unit for displaying letters, symbols, patterns, and so on is capable of being constructed small in size and allowing low power consumption as compared with a cathode-ray tube. It is, therefore, suitable for use as measuring equipment, office equipment, or a terminal for a computer. Flat panel display units are known which utilize electroluminescence, plasma or fluorescent display tubes, LEDs and so on. In particular, an LED display unit is considered to be promising as a flat panel display unit since the drivers for it may be simple in construction, multicolor display is possible, and the manufacturing cost may be reduced.
Since the picture elements, that is, the display points increase in number with an increase in the display area with a flat panel display unit, it is not easy to manufacture a single flat panel display unit having a great display area, and it is also difficult to repair the such single flat panel display unit. Thus, it has been proposed that a number of LED modules be combined to manufacture a flat panel display unit. However, such a combination has been unsuitable for conventional LED modules. An LED flat panel display device by T. Niina and S. Kuroda as described in the Conference Record of 1978, Biennial Display Research Conference, SID, Oct. 24-26, 1978, pages 18-19, is used as a single unit and is not intended for use in combination. In contrast with this, Ronald L. Harris describes an LED module in the Conference Record of 1978, Biennial Display Research Conference, SID, Oct. 24-26, 1978, pages 20 to 21, in which no LED pellets are arranged in a peripheral region having a width exceeding the pitch of the adjacent picture elements, that is, the display points. Therefore, with a flat panel display unit combining these modules, the pitch of the picture elements of the adjacent modules is different from the pitch of the picture elements inside the modules, possibly resulting in a distorted or unclear displayed image.